The winged mapleleaf, also known as false mapleleaf, or hickory nut shell, and with the

scientific name In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''Quadrula fragosa'', is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

freshwater mussel Freshwater bivalves are molluscs of the order Bivalvia that inhabit freshwater ecosystems. They are one of the two main groups of freshwater molluscs, along with freshwater snails. The majority of bivalve molluscs are saltwater species that l ...

. It is an

aquatic Aquatic means relating to water; living in or near water or taking place in water; does not include groundwater, as "aquatic" implies an environment where plants and animals live. Aquatic(s) may also refer to: * Aquatic animal, either vertebrate ...

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

in the family

Unionidae The Unionidae are a Family (biology), family of freshwater mussels, the largest in the order Unionida, the bivalve molluscs sometimes known as river mussels, or simply as unionids. The range of distribution for this family is world-wide. It is a ...

, the river mussels. It is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

. ''Quadrula fragosa'' is only located in a few parts of

Wisconsin Wisconsin ( ) is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest of the United States. It borders Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michig ...

Minnesota Minnesota ( ) is a U.S. state, state in the Upper Midwestern region of the United States. It is bordered by the Canadian provinces of Manitoba and Ontario to the north and east and by the U.S. states of Wisconsin to the east, Iowa to the so ...

Arkansas Arkansas ( ) is a landlocked state in the West South Central region of the Southern United States. It borders Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma ...

, and

Missouri Missouri (''see #Etymology and pronunciation, pronunciation'') is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it border ...

— in the

Midwestern United States The Midwestern United States (also referred to as the Midwest, the Heartland or the American Midwest) is one of the four census regions defined by the United States Census Bureau. It occupies the northern central part of the United States. It ...

. It is a federal critically endangered river mussel species.

Description

The anterior end of the ''Quadrula fragosa'' shell is slightly rounded and the posterior end of the shell is more of a square shape. The shell can range in color from a yellowish-green to light or dark brown. The inside of the shell is white, and there is sometimes iridescent coloring at one end of the shell. The diameter of a mature mussel of this species is usually about 4 inches (10.2 cm). The shells of these mussels are very thick, and unlike many other mussels, there are bumps on the shell surface running down from the hinge of the shell to the outside edges. It is the patterns of these bumps that help to distinguish the winged mapleleaf from many other mussels that look very similar in appearance.

Habitat

The winged mapleleaf is found in medium to large streams and rivers. it can sometimes be found in the mud, but it is more commonly either found in gravel or sandy bottoms. The mussel does need to be in moving water in order to survive, the depth of this running water also needs to be somewhere between 0.4 and 2.0 meters. The water must be free of pollutants and clean.

Range

At one time the winged mapleleaf could be found in thirteen states. It lived in nearly all the rivers and streams that flow into the

Mississippi River The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...

. It was once also found in some rivers and streams that flow into the

Missouri River The Missouri River is a river in the Central United States, Central and Mountain states, Mountain West regions of the United States. The nation's longest, it rises in the eastern Centennial Mountains of the Bitterroot Range of the Rocky Moun ...

. Today however, the mussel can only be found in four or five river systems in the Midwestern United States, and only found in limited areas of those rivers: in a five-mile stretch of the St. Croix River, which flows between the states of

and

; In

it can be found in the

Ouachita River The Ouachita River ( ) is a river that runs south and east through the United States, U.S. U.S. state, states of Arkansas and Louisiana, joining the Tensas River to form the Black River (Louisiana), Black River near Jonesville, Louisiana. It i ...

and also the Saline River; some populations have been located in the Bourbeuse River in

as well as the

Little River Little River may refer to several places: Australia Streams New South Wales *Little River (Dubbo), source in the Dubbo region, a tributary of the Macquarie River * Little River (Oberon), source in the Oberon Shire, a tributary of Coxs River (Haw ...

Oklahoma Oklahoma ( ; Choctaw language, Choctaw: , ) is a landlocked U.S. state, state in the South Central United States, South Central region of the United States. It borders Texas to the south and west, Kansas to the north, Missouri to the northea ...

. Of these locations, the population of these mussels in the St. Croix River is the only one that has been proven to actually be persistent. Winged mapleleaf mussels in the Ouachita and Saline Rivers may have a viable population. It is currently estimated that there are somewhere between 10,000 and 100,000 surviving individuals rangewide.

Feeding

The mussel filters out tiny food particles, either phytoplankton or zooplankton. The young winged mapleleafs attach themselves to the gills of a host fish for feeding and growing purposes until they reach the stage in their life cycle that they can themselves siphon in the water from the river of the stream that they are in.

Reproduction

Reproduction of the winged mapleleaf is very similar to that of many other freshwater mussels. The males release their sperm into the water, then as the females siphon in water the sperm fertilizes the eggs which are located on their gills. After fertilization the eggs develop into a larva, and once the larva reaches a certain stage it is released from the gills of the mother mussel into the river current. The larva then must reach the gills of a host fish where it can then continue its growing process. The only currently known host fish are the

channel catfish The channel catfish (''Ictalurus punctatus''), known informally as the "channel cat", is a species of catfish native to North America. They are North America's most abundant catfish species, and the official state fish of Kansas, Missouri, Nebra ...

and the

blue catfish The blue catfish (''Ictalurus furcatus'') is a large species of North American catfish, reaching a length of and a weight of . The continent's largest catfish, it can live to 20 years, with a typical fish being between and . Native distribution ...

. The larva continue growing on the host fish until they reach their next life cycle stage, and once this stage is reached they are released from the gills of the host fish and find their way to the bottom of the river or stream. Once they have reached the bottom, they then begin maturing into the adult stage of their life cycle. The actual reason for the channel catfish and the blue catfish being the only host fish to successfully have a larva mature on them is still unknown. Research was even done by a group of researchers where they used divers to see if they could plant the larva from the mother onto the gills of fish other than the two kinds of catfish. The research was limited from a number of different causes, a limited number of eggs found in the area to transplant on to captive fish, and also the deal of many of the fish that they had captive. The results, however they were very limited, still only showed the Channel and the Blue catfish to be successful host fish for the winged mapleleaf. The oldest known organism in this species is in the St. Croix River and is estimated to be 22 years old, although, the life span of the mussel is actually unknown.

Threats

The winged mapleleaf currently faces a number of different threats to its survival. The invasion of the

Zebra mussel The zebra mussel (''Dreissena polymorpha'') is a small freshwater mussel, an Aquatic animal, aquatic bivalve mollusk in the family Dreissenidae. The species originates from the lakes of southern Russia and Ukraine, but has been accidentally Intro ...

''Dreissena polymorpha'', (which the U.S. Fish and Wildlife Service trying to control) is one of the biggest threats to the survival of the winged mapleleaf. The Zebra mussel is an extremely invasive species and in 2000 the Zebra mussel began being a problem in the St. Croix River. Sediment accumulation and loss of water quality are also major threats to the population of the mussel. The reproducing population in the St. Croix River area is near the metropolitan area of St. Paul, and as the larger cities begin to become further developed, sediment is dispersed into the river and more and more pollution occurs. This can also change the flow of the river, causing erosion and a change in water levels. The winged mapleleaf needs to be in a clean environment and can only survive in certain water levels. Upstream dam operations also cause changes in the water level, which is another issue that the U.S. Fish and Wildlife Service is trying to take action towards. The biggest issue that the mussel currently faces right now is that there is only one known reproducing population. This means that a severe rainstorm that caused flooding, a pollution spill, or the outbreak of an upstream dam could easily wipe out the entire population and cause this mussel species to become extinct.

Extinction preventions

The winged mapleleaf was added to the list of endangered and threatened plants and animals effective July 22, 1991. It is now illegal to collect, harm, threaten, or kill the mussel. Permits can be issued from the U.S. Fish and Wildlife Service to give individuals rights to collect some individuals to conduct research projects, but these permits are not easily attained. The State of Wisconsin and the state of Minnesota are working with the help of the U.S. Fish and Wildlife Service to try to control the invasion of the Zebra mussel. There is also currently an experimental population of the winged mapleleaf that has been released into the wild. This experimental population was released in parts of the Tennessee River in Colbert and Lauderdale counties. Whether or not these released populations are reproducing, has yet to be proven. Many of the upstream dam operations have also begun to be more closely monitored in order to ensure that there is an adequate flow of water in the St. Croix River for the winged mapleleaf to survive and reproduce. The levels of the river are being kept between the constant 0.4 and 2.0 meters that the mussel needs in order to survive.

References

Sources

* Bauer, Gerhard. Ecology and Evolution of the Freshwater Mussels. 2001. Springer Publishing * Steingraber, Mark. U.S. fish and wildlife Service. Fort Snelling, MN http://www.fws.gov/midwest/LaCrosseFisheries/projects/mapleleaf.html * Endangered species facts lectronic resource: winged mapleleaf Electronic books U.S. Fish and Wildlife Service. ashington, D.C.: U.S. Fish and Wildlife Service,

004 004, 0O4, O04, OO4 may refer to: * 004, fictional British 00 Agent * 0O4, Corning Municipal Airport (California) * O04, the Oversea-Chinese Banking Corporation * Abdul Haq Wasiq, Guantanamo detainee 004 * Junkers Jumo 004 turbojet engine * La ...

Online Access * Endangered species facts lectronic resource Electronic books U.S. Fish and Wildlife Service. ashington, D.C.: U.S. Fish and Wildlife Service, 001 Online Access * Host fish identification and early life thermal requirements for the federal endangered winged mapleleaf mussel lectronic resource Electronic books Upper Midwest Environmental Sciences Center (Geological Survey). La Crosse, Wis. : U.S. Dept. of the Interior, U.S. Geological Survey, Upper Midwest Environmental Sciences Center,

005 ''005'' (pronounced "''double-o five''") is a 1981 arcade video game by Sega. They advertised it as the first of their RasterScan Convert-a-Game series, designed so that it could be changed into another game in minutes "at a substantial savings. ...

Online Access * Hornback, Daneil; March, James; Deneka, Tony; Troelstrup, Nels; Perry, James. "Factors Influencing the Distribution and Abundance of the Endangered Winged Mapleleaf Mussel Quadrula fragos in the St. Croix River, Minnesota and Wisconsin." American Midland Naturalist Volume 136.October, 1996 278-286. Accessed April 15, 2008 * Bleam, Daniel, Cope, Charles; Couch, Karen; Distler, Donald. "The Winged Mapleleaf, Quadrula fragosa in Kansas." Transactions of the Kansas Academy of Science Volume 101(1998) 35-38. April 17, 2008 * Steingraeber, Mark, Bartsch, Michelle; Kalas, John; Newton, Teresa. "Thermal Criteria for Early Life Stage Development of the Winged Mapleleaf Mussel (Quadrula fragosa).." American Midland Naturalist 157(2006) 297-311. April 17, 2008 {{Authority control Quadrula Endemic molluscs of the United States Critically endangered fauna of the United States Bivalves described in 1835 Taxonomy articles created by Polbot